The invention relates to a swivel-and-tilt type holder for an electric lamp.
It is known in the art to provide a swivel-and-tilt type lamp holder which is provided with a sleeve which is rotatably mounted upon the end of a tubular bracket, and with a rod supported within the sleeve and capable of being rotated about an axis vertical to the axis of sleeve rotation. In such a lamp holder, the rod is screwed into the rear end of a standard lamp holder, and the holder as well as the joint are then surrounded by a clamped-on cylindrical tube.
A principal disadvantage of the prior art type of lamp holder is the complexity of construction of the joint mechanism since the several components of the joint must then be manufactured to quite close tolerances. Failure to observe close tolerances causes premature wear at the joint with the result that insufficient positive coupling of the parts results so that the lamp will not maintain a preset position but will move therefrom as a result of its own weight.